The distant Universe, as viewed here through the plane of the Milky Way, consists of stars and galaxies, as well as opaque gas and dust, going back as far as we can see. But we know we aren’t seeing it all, no matter how we look. Image credit: 2 Micron All Sky Survey (2MASS).

Ask Ethan: How Much Of The Observable Universe Are We Failing To See?

There’s so much that we’ve discovered, looking as deeply as possible into the void. But what are we missing?

Start with the laws of physics, a Universe full of a specific amount matter and radiation, and a hot, dense, expanding, and mostly uniform state, and wait. 13.8…